Forces and Motion

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Forces and Motion
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According to Newton (and the laws of science)
Everythings in Motion!
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The question is

• Why does everything in the universe move?

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The answer

• Big, huge, massive forces!

And little ones too.
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What are they and what do they do?

• A Force is a pull (an attraction)

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What are they and what do they do?

• Or, a push (a repulsion)

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You have to keep an eye on Forces, because they
make things change.

• They can change your direction or speedin an
  instant.

Boom!
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And Forces are trickythey can also cancel each
other out!
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And there are lots of Forces out there count
em
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• Gravity
• Electromagnetic
• Strong Nuclear and
• Weak Nuclear

FOUR Forces. Easy to say. Easy to remember.
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Gravity

• The first one, Gravity (or G Force), reigns
  supreme. Why, you ask?
• Its all about the range.

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Nuclear

• Strong and Weak Nuclear Forces? They have very
  short rangesless than one hundred millionth of a
  human hair!
• Electromagnetic Force? It has a long range, but
  it doesnt have a large net electric charge.
  Bummer.
• Gravity
• But Gravity? Gravity runs over any range and
  affects anything with mass.

E l e c t r o m a g n e t i c
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Yep, Gravity rules.

• Its also important for life. Without it, the Sun
  would be lonelynot attracted to the Earth at all!

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Gravity is the real deal. So lets explore this
G-Force more!

• The gravitational force (or Fg) between two
  objects depends on each objects mass
• The Force gets stronger as the total mass of the
  objects gets bigger.

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Gravitational Force

• Gravitational force is the attraction between all
  masses in the universelike the attraction of the
  earth's mass to bodies (like ours) near its
  surface. And it looks like this

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In math lingo, you might say

• The gravitation between two bodies is
  proportional to the product of their masses and
  inversely proportional to the square of the
  distance between them.

Gravitational Force
universal gravitational constant
distance between the two objects
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But dont worry, as Albert Einstein said
Gravitation cannot be held responsible for people
falling in love.

• Phew!

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First Law of Motion

• Now we know that Gravity is a serious Force, but
  it can be confusing. Thats where our man Isaac
  Newton comes in to help with his First Law of
  Motion
• Objects at rest (or in motion) stay that way
  unless acted on by an outside Force.

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Discussion Questions

• What is the object here?
• Is it in motion or at rest?
• And what is the Force that acts on the object?

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Then comes Newtons Second Law of Motion

• FMa Force equals Mass times acceleration.
• In other words, Forces make mass move by
  accelerating it.

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Discussion Questions

• What changed when the size of the soccer balls
  changed?
• How did this change (from a small soccer ball to
  a gigantic one) affect the acceleration?
• Why?

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And Newtons Third Law is a charm

• Action Reaction
• For every action there is an equal and opposite
  reaction.

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Discussion Questions

• What was the action here?
• What was the reaction?
• Can you explain how that action caused a reaction?

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Lets recap

• Objects at rest (or in motion) stay that way
  unless acted on by an outside Force.
• Force Mass times acceleration (FMa)
• For every action there is an equal and opposite
  reaction.
• And sometimes, they all happen at once!

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Discussion Questions

• What was the object in motion?
• What was the outside Force?
• What was the mass?
• What action caused the reaction?
• Do you like cream pie?
• Why?

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• In FMA Live!, we can point out examples of things
  that Forces act on. Like the force of gravity
  pulling the rocket back toward the ground.

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Discussion Questions

• What are some other examples of people or things
  in your every day life that Forces act upon?

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• Make Newton proud and be your own Force.
• Let your imagination shoot high into the sky.
• Learn all you can nowAnd who knows how far
  youll go!? Maybe to Mars and beyond!